For example, the inventor proposes, in Patent Literature 1, a contact lens for changing a shape of the cornea of a patient by being mounted during sleep and the like, and correcting myopia and/or astigmatism at the time when the contact lens is removed. Subsequently, the inventor has also developed a similar contact lens for correcting hyperopia.
As shown in FIG. 7, in a contact lens 1A for correcting myopia as described above, a relief region 3 constituted by a concave portion and a pressing region 4 constituted by a convex portion are formed on a side of the lens in contact with a cornea 2 of a patient. By pressing the relief region 3 and the pressing region 4 to the cornea 2, a part of the cornea is pushed downward by the pressing region 4 and, as a reaction thereof, a part of the cornea 2 is projected into the relief region 3, so that the cornea 2 is corrected into a shape in which desirable naked eye vision can be obtained or a shape in which keratoconus cornea is smoothly suppressed.
As shown in FIG. 8, in a contact lens 1B for correcting hyperopia, a relief region 5 and a pressing region 6 are reversed to each other as compared to the case of correcting myopia.
In the contact lens 1A for correcting myopia, the pressing region 4 is formed to project in a convex curved-surface shape at a position corresponding to the center of the corneal dome to be pressed when the contact lens 1A is mounted on the cornea 2. In contrast, the relief region 3 is constituted by an annular concave portion that has a cross section in a concave circular arc shape at a position encircling the outer periphery of the pressing region 4, and configured such that a part of the cornea 2 enters the annular concave portion thereof as a reaction of the cornea 2 pushed downward by the pressing region 4. The contact lens 1A also includes an anchor region 7 having a shape aligned with a contour of the cornea 2, when the contact lens 1A is mounted on the cornea 2, at a position encircling the outer periphery of the relief region 3, and a peripheral portion 8 further encircling the outer periphery of the anchor region 7.
When the above-mentioned contact lenses 1A and 1B are not put on for a long period, myopia or hyperopia is returned to its original condition by a restoring force of the cornea, thus it is desirable that the cornea be fixed in a corrected state.
On the other hand, there has been known a refraction correction surgery in which a corneal tissue in a state of being infiltrated with riboflavin (vitamin B2) is irradiated with ultraviolet rays for crosslinking collagens constituting the cornea to one another, thereby enhancing strength of the cornea and fixing the cornea.
It is expected that a shape of the cornea can be fixed to some extent in a state of being corrected by a contact lens by combining this crosslinking method and the above-mentioned contact lenses (publicly unknown).
However, although the above-described crosslinking can suppress the progress of keratoconus cornea of a patient, eyesight varies after the crosslinking and it is difficult to correct eyesight to be normal. As such, it is speculated that there is a high probability of being unable to recover eyesight as aimed even when the above-mentioned contact lenses for correction are used.
Further, apart from the contact lens for vision correction, there is a color contact lens for dress up.
This color contact lens for dress up is composed of a central portion corresponding to the pupil and an annular portion arranged on the outside thereof. The annular portion is applied with annular coloring while the central portion is uncolored, and this contact lens does not have an eyesight correcting function.
The conventional contact lens for vision correction or the color contact lens for dress up have, for example, such problems that they cannot be used in the case of diseases such as dry eye and that the center of these lenses is shifted from a position of the pupil during the wearing thereof. Further, a portion of the lens corresponding to the central portion of the corneal dome or the pupil needs to be transparent, and thus there is a problem that a 3D printer forming a final product in an opaque state cannot be used for forming the lens.